The invention relates to a device for cooling products to be cooled, the device having a carrier for the products to be cooled, a housing and an inlet for supplying a cooling medium into the interior of the housing as well as at least one opening of the housing for supplying and extracting the product to be cooled.
A number of measures are known for directing gas in the case of installations for cooling and freezing products to be cooled. After its use for cooling purpose, the cooling medium, as a rule, leaves the installation in a gaseous state. Preferably, nitrogen or carbon dioxide can be used as cooling media; they are particularly suitable for this purpose as low-temperature gases.
The term “cooling”, on the one hand, describes the cooling to temperatures above the freezing point, for example, the cooling of heat-treated food products from +70° C. to +2° C. However, “cooling” comprises particularly also freezing and deep freezing. “Deep freezing” means that the food products are subjected to a refrigerating medium of a sufficiently low temperature for a sufficient period of time, so that, following the freezing process, a core temperature exists which is clearly below the freezing point of water; as a rule, below a temperature of −18° C.
The refrigerating medium can, for example, be low-temperature gas (liquefied or gaseous) or cooled air. As a rule, the heat exchange takes place essentially by way of convective processes. When liquefied gas is used, it also takes place by way of heat conduction by direct contact of the cooling medium with the product to be cooled.
Preferably, the gas is therefore introduced into the cooling device in a liquefied state and is vaporized by a thermal transfer from the product to be cooled to the cooling medium. The then warmer and gaseous cooling medium is discharged from the cooling device. The discharge should normally not take place into the environment of the installation because the above-mentioned gases displace the air and thereby would endanger people in the surroundings of the installation. Thus, for reasons of safety, a removal of the gas has to be ensured from the working environment of such a cooling device.
For this purpose, it is known to remove by suction the gas in the interior of a cooling device or directly above or below the feeding or delivery point for the products to be cooled. However, these measures have the common disadvantage that a suction is oftentimes generated inside the cooling device and, as a result, not only heated gas is removed by suction, thus gas which has already served its cooling purpose, but also low-temperature gas which, had it remained in the cooling device longer, would still have been able to absorb heat.
It is therefore an object of the invention to design a device such that an efficient utilization of the used cooling medium is achieved; in particular, that the removal is low with respect to losses for the cooling medium.
This object is achieved in that at least one channel or conduit for receiving cooling medium is provided in the area of the opening, this channel being operatively connected with a suction-side connection of a fan and having an inlet opening arranged outside the housing laterally next to the opening of the housing.
A channel arranged in such a manner has the advantage that the cooling medium (for example, nitrogen or carbon dioxide), which is preferably fed in a liquefied state to the device for being cooled and evaporates as a result of heat transfer from the products to be cooled to the cooling medium, is removed by suction immediately after exiting the housing. An important advantage consists of the fact that essentially only heated gaseous cooling medium, thus cooling medium which has already met its cooling purpose, is removed, while a removal by suction of cooling medium which has not yet absorbed the intended amount of heat from the interior of the housing is avoided.
This is also reliably avoided in the case in which the suction power of the fan is higher than the amount of heated cooling medium to be discharged per time unit. Specifically, in this case, ambient air from the environment of the device is taken in as the differential quantity, the taking-in of the ambient air being considerably promoted by the arrangement of the inlet opening of the channel.
For this case, according to an advantageous further development of the invention, an intake connection piece for taking in ambient or environmental air is additionally provided in front of the fan. As a result, an ice formation is avoided inside the fan. An ice formation may occur in the fan if the moisture content of the taken-in gas is too high. For this reason, dry ambient air is preferably admixed as required.
Another advantage consists of the fact that, as a result of the lateral arrangement of the channel according to the invention, a contact is prevented between the products to be cooled and the condensation water caused by contact of the gas with the comparatively warm surface of the channel during the removal by suction in the channel.
The channel preferably has a rectangular cross-section. Particularly preferably, the inlet opening of the channel has a rectangular cross-section. The longer side of this rectangle is advantageously arranged essentially parallel to the longitudinal axis of the carrier of the products to be cooled.
This further development permits a very efficient discharge of the gas flowing out of the housing without influencing the flow conditions inside the opening. Particularly advantageously, this further development is also suitable for additionally facilitating the taking-in of a differential amount of ambient air. The case in which such a taking-in of ambient air is desirable was described above.
According to another advantageous further development of the invention, the channel has a round or elliptical cross-section. The advantage is the result of the adaptation of the cross-sectional shape of the channel to the geometry of the opening of the housing, so that a removal by suction is achieved which is as complete as possible.
The carrier of the products to be cooled is expediently constructed as a conveying belt. During the cooling, the products to be cooled are moved, for example, through a tunnel-type deep freezer or through a spiral deep freezer.
Another expedient further development of the invention provides a foil as a carrier for products to be cooled, which foil is preferably moved through the deep freezer like a conveying belt.
Another expedient embodiment of the invention provides a current of liquid nitrogen as a carrier for products to be cooled, which current flows through the deep freezer and moves the products to be cooled in a floating or immersing manner on or in the liquid nitrogen.
In another advantageous embodiment of the invention, the channel has a slope from the inlet opening, which is arranged laterally next to the opening of the housing, down to a lowest point, at which a discharge connection piece is mounted for the discharging of liquid, particularly a discharge connection piece for discharging condensation water and/or cleaning solution. As a result, an undesirable contact of the liquid with the products to be cooled is reliably prevented.
According to a particularly expedient embodiment of the invention, two channels are provided, particularly two channels arranged laterally next to the opening and in a mutually opposite position. This results in the advantage of a uniform removal of the gas.
The invention has a number of additional advantages:
As a result of the removal by suction according to the invention, the flow conditions are not impaired in the interior of the housing in which the cooling is taking place, and no undesirable suction is generated in the interior of the housing. This permits a very efficient utilization of the cooling medium. The demand for cooling medium is clearly reduced in comparison to conventional solutions. The invention therefore offers important advantages in the fields of energy efficiency and of the economical use of operating media, such as cooling medium.
Furthermore, a large number of hygienic demands are met by means of the invention in a simple manner. In addition, care is taken that the personnel loading products to be cooled into the deep freezer are protected from injuries. Likewise, by means of the design of the removal by suction according to the invention, it is reliably prevented that products to be cooled which accidentally fall beside the conveying belt fall into the removal suction.
The invention as well as additional details of the invention will be explained in detail in the following by means of an embodiment illustrated in the drawings.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.